Smad2^{tm4(SMADH3)Rob}

A targeting vector was designed to subsequently delete exon 2 coding sequence and insert the amino-terminal flag-tagged human SMAD3 cDNA into the locus. A triply repeated SV40 polyA sequence was inserted to ensure transcriptional termination as well as a floxed PGK-neo. Transient cre expression excised the floxed neo. Ribonuclease protection assay probes were designed to confirm expression of the human cDNA, and residual endogenous transcripts were barely detectable in mutant tissues. Recombined transcript expression levels in mutants were comparable to that of endogenous levels in wild-type animals. (J:95374)